Reversible wear plate pump



0 1 61 t G. Dops N Em 3,348,49

REVERSIBLE WEAR PLATE PUMP Filed Dec. 5, 1966 5 Sheets-Sheet 1fi/ezz/an? 51455222 Z1 P652 /ofizz Gfald 0502b Filed Decv 5, 1966 G. D.OLSON ETAL REVERSIBLE WEAR PLATE PUMP 5 heets-Sheet 2 em/dfl 0419022 10d. 1967 G. D. OLSON ETAL 3,348,492-

REVERSIBLE WEAR PLATE PUMP Filed Dec. 5, 1966 5 Sheets-Sheet 4 5 0115'E2 Uwzizz E] 6Z i jafzzz Gerald ,F. dawn a 1/ KMX. 34

Oct. 24, 1967 OLSON ETAL 3,348,492

REVERSIBLE WEAR PLATE PUMP Filed Dec. 5, 1966 5 Sheets-Sheet 5 5517- gga 28 5719 IIIIHUIIIII H g Fwd}? 3,348,492 REVERSIBLE WEAR PLATE PUMPGerald 1). Olson and Austin E. Pettyjohn, Auburn, Ind.,

assignors to Borg-Warner Corporation, Chicago, Ill., :1

corporation of Illinois Filed Dec. 5, 1966, Ser. No. 599,237 12 Claims.(Cl. 103-126) ABSTRACT OF THE DISCLOSURE A pressure loaded pump or motorhaving a pair of intermeshing gears mounted within a housing having aninner-peripheral surface defining a cavity, the housing.

having low pressure and high pressure ports. A wear plate mountedbetween the gears and an end wall of the cavity, the wear plate having apressure loading zone defined thereon n the side of the wear platetoward the end wall of the cavity, the zone being defined by a sealmounted in a groove of the wear plate. The seal is adapted to moveoutwardly in response to the fluid pressure underneath the seal. Thewear plate is so constructed that it is movable axially to load the pumpgears and provide an effective seal therebetween and is also movableradially to engage the inner peripheral surface of the cavity so that ineither direction of rotation the wear plate will move radially to engagethe inner peripheral surface of the cavity on the opposite side of theperiphery of the wear plate from the high pressure port of the pump ormotor to provide a fluid seal between the periphery of the wear plateand the inner peripheral surface of the cavity.

Summary of invention This invention relates to a pressure loaded pump ormotor of the wear plate type and more particularly to a pressure loadedpump or motor mechanism adapted to be reversible in operation. 7

'This invention relates to an improved reversible pressure loaded pumpor motor of the wear seal plate type, the wear plate being movableradially to engage the inner peripheral surface of the pump or motorcavity and movable axially to sealably pressure load the gears. The wearplate has a seal on the face thereof toward the end wall which isactivated by fluid pressure underneath the seal to engage the end walland define pressure loading zones on the wear plate. The wear platemoves radially to engage the peripheral surface ofthe pump or motorcavity on the opposite side of the periphery of the wear plate fromwhich the high pressure is located depending upon the direction ofrotation of the pump or motor.

Other features and advantages of the present invention will be apparentfrom the following description when read in connection with theaccompanying drawings in which:

FIGURE 1 is an end view of the pump incorporating the features of thepresent invention; 7

FIGURE 2 is a sectional view along line 22 of FIGURE 1; 7

FIGURE 3 is a sectional view along, line 33 of FIGURE 2; v FIGURE 4 is asectional view taken along line 4-4 of FIGURE 3;

FIGURE 5 is a sectional view taken along the line 55 of FIGURE 3;

FIGURE 6 is a sectional view taken along the line 6-6 of FIGURE 3;

FIGURE 7 is a view of the wear plate of the present invention;

ice

FIGURE 8 is a sectional view taken along the line 8-8 of FIGURE 7;

FIGURE 9 is a view of the gear engaging side of the wear plate of thepresent invention;

FIGURE 10 is a representation of the seal in plan view;

FIGURE 11 is an end view of the seal of FIGURE 10;

FIGURE 12 is a view of the opposite side ,of the seal of FIGURE 10;

I FIGURE 13 is a cross sectional view of the wear plate taken along theline 1313 of FIGURE 7;

FIGURE 14 is an enlarged view of the seal assembled in the wear plate; 7

FIGURE 15 is a view similar to FIGURE 14 showing the compression of theseal after assembly in the pump;

FIGURE 16 is an enlarged view of an optional form of seal;

FIGURE -17 is a view of the resilient member to be utilized in amodified form of seal construction;

FIGURE 18 is an end view. of the resilient member of FIGURE 17;

FIGURE 19 is a view of the opposite side of the resilient member ofFIGURE 17;

- FIGURE 20' is a view of the seal member used in I seal member ofFIGURE 24 is an end view taken along the line 2424 ofFIGURE 19. 7 Thedevice of the present invention is generally similar to that disclosedin co-pending application Ser.

No. 609,686, filed Jan. 16, 1967 of common assignee, which is acontinuation application of Ser. No. 572,494, filed Aug. 15, 1966, nowabandoned, to which reference may be had for additional descriptionofthe details and operation of a uni-directional type of wear ,platepressure loaded pump or motor.

Referring to FIGURES l, 2 and 3, a pump or motor 10 is illustrated whichmay employ the present invention therein. The device 10 includes a bodyor housing 11 and an end cover 12. The device will generally bedescribed as a reversible pump in the ensuing description; however, itwill be obvious to those of ordinary skill in the art that by utilizinga separate source of pressure the device 10 will function as areversible fluid motor.

Mounted within the pump are gears 13 and 14 which intermesh and whenrotated are operative to pump fluid. Journals 16 are provided for thegears 13 and 14. One of the journals 16 for the gearing includes anextension 17 having a keyway 18 therein engageable by a key 19 toprovide the driving connection to turn the gears when connected to apower source. The journals 16 for the gears 13 and 14 are mounted in apair of bores 20 within the cover 12 and in a pair of bores 21 providedin the body 11. The cover member 12 may be secured to the body 11 by anyknown means as for example by bolts 22.

. A cavity 24 is provided in body 11 in which gears 13 and 14 aremounted. The cavity 24 is defined by an inner peripheral surface 25 ofgenerally a figure 8 cross-section, as will be clear from FIGURE 4, aninner face or end wall 26, and the cover 12. An improved wear plate 30is provided which is mounted in the cavity 24 between which areinterchangeably high and low pressure ports depending upon the directiongears 13 and 14 are driven when the device is used as a pump ordepending upon the port to be supplied from a source of pressure whenthe device is used as a fiuid motor. Mating with the ports 34 and 35 isa pair of recesses 36 and 37 respectively provided in the cavity 24. Therecesses 36 and 37 provide for easy entrance and exit of fluid into andfrom the device 10 by means of the ports 34 and 35 in the cover 12.

Referring to FIGURES 7, 8 and 9, the wear plate 30 of the presentinvention is disclosed. The wear plate 30 is of a generally figure 8configuration having an outer peripheral surface 40 and a pair of bores41 and 42 adapted to receive the journals 16 and 16a. As seen in FIGURE9, the bores 41 and 42 are larger in diameter than the journals 16 and16a, preferably from .018 to .023 inch when the bores are .665 inch indiameter, to provide a clearance 43 between the wear plate 30 and thejournals 16 so as to provide for a limited radial movement of wear plate30 within cavity 24 as will be later described and also to preventbinding of the wear plate when it moves transversely as will be laterdescribed.

The wear plate 30 has a side face 45 adapted to engage the gear sidefaces 32. The wear plate 30 also has a face 47 on the opposite sidethereof adapted to be in close association with the inner face or wall26 of the pump body 11. A pocket 50 is provided in the pump body whichis of generally complementary shape to the wear plate 30 which isadapted to receive the wear plate 30 as can be seen in FIGURE 3, forexample. The inner peripheral surface 25 of the pump body is continuousand defines an inner peripheral surface in the area of the wear plate30.

The outer peripheral surface 40 of wear plate 30 is relieved at theupper and lower ends as illustrated in FIG- URE 7 and as indicated at 53and 54. The outer peripheral surface 40 is further relieved on the sidesthereof as indicated at 55 and 56. Relieving of the outer peripheralsurface at areas 53, 54, 55 and 56 just described leaves a pair ofarcuate sealing surfaces 58 and 59 on the right side thereof as viewedin FIGURE 7 and a pair of arcuate sealing surfaces 60 and 61respectively on the left side thereof as viewed in FIGURE 7. The sealingsurfaces 58, 59, 60 and 61 are adapted to engage the inner peripheralsurface 25 of the pump body 11 to perform a sealing function as willlater be described.

The wear plate 30 has a central axis 65 which intersects centers of thebores 41 and 42 therein. On the face 47 of the wear plate a continuousgroove 66 is provided which is generally of a figure 8 shape surroundingeach of the bores 41 and 42 in the wear plate 30. The groove 66 has fourradially projecting sections extending from the circular or figure 8parts of groove 66 to the peripheral arcuate sealing surfaces of thewear plate. Radial grooves 70, 71, 72 and 73 extend between the figure 8sections of the grooves 66 and the outer peripheral sealing surfaces 58,59, 60 and 61 respectively. The continuous groove 66 including itsradial extensions above described is symmetrical about the axis 65 ofthe wear plate so as to provide for the reversible operation of thepressure loading wear plate 30.

In the recessed area 53 of the wear plate and on the face 47 is a pairof radially extending recesses 75 and 76. In the recessed area 54 of thewear plate is a pair of radially extending access recesses 77 and 78. Ascan be seen from FIGURE 8, the access recesses are of greater depth thanthe continuous groove 66 and serve to supply fluid pressure to thebottom portion of the groove 66 at each of the four access recesses soas to actuate a fluid pressure seal during operation of pump'10 as willbe later described. The access recesses 75, 76, 77 and 78 extendradially from the continuous groove 66 to the recessed portions 53 and54 of the outer peripheral surface of the wear plate. Also the accessrecesses are all interposed between a pair of the outer peripheralsealing surfaces. For example, access grooves 75 and 76 are locatedbetween the outer peripheral sealing surfaces 58 and 6t and the accessrecesses 77 and 78 are located between the outer peripheral sealingsurfaces 59 and 61.

A continuous seal 80 is illustrated in FIGURES 10, 11 and 12 which iscomplementary to and of identical shape to the continuous groove 66 ofthe wear plate and is adapted to be assembled therein. The continuousseal 80, therefore, similar to the continuous groove 66, has fourradially projecting arms connected to the figure 8 sections thereofwhich are 81, 82, 83 and 84 and which are adapted to be received by theradial groove sections 70, 71, 72 and 73 respectively of continuousgroove 66.

Illustrated in FIGURE 13 is a cross section showing the seal 80assembled within the continuous groove 66. FIGURES 14 and 15 areenlarged views illustrating the seal member 88 assembled within thegroove 66. From the enlarged view it can be seen that the seal member 80has a generally flat surface 86 thereon adapted to engage the face 26 ofthe body 11 and also includes a pair of projecting lips 87 and 88 whichdefine therebetween a fluid conducting channel 89. As seen in FIGURES l4and 15, the groove 66 includes side walls 91 and 92 and a bottom wall93. The lips 87 and 88 are adapted to engage side walls 91 and 92 whenseal 80 is assembled in the groove 66. FIGURE 14 illustrates the sealjust prior to final assembly in the pump, the seal being loosely placedwithin the groove 66 and the lips 87, 88 loosely engaging sides 91 and92 of groove 66. After final assembly of the pump, the seal will assumethe position illustrated in FIGURE 15 wherein the lips 87 and 88, due tothe axial force moving seal 80 further into the groove 66 in assemblyand deflecting the lips 87 and 88 inwardly toward the central passage 89in the seal 80 as illustrated in FIGURE 15. Due to the deflection of thelips 87 and 88 and the resilient characteristic of the material used inseal 88, a resultant axial force will exist inherent in the seal 80attempting to move the seal 80 out of the groove 66 and thereby intoengagement with the surface or inner face 26 of the body 11. Thus, priorto pump operation a preload function is present in that the seal will beinitially urged by the preloading into engagement with the surface orface 26 and further the wear plate 30 will be urged by the same forceinto engagement with the gears 13 and 14.

During operation of the pump fluid pressure will be admitted into thefluid passage in groove 66 in the wear plate as defined by side walls91, 92 and bottom wall 93 and the passage 89 of seal 80. The fluid willthus be conducted underneath seal 80 and throughout the entirecontinuous extent of the groove 66 and during pump operation will urgethe seal 80 further into engagement with face 26 to define a pressureloading zone or other face 47 of wear plate 30, as will be laterdescribed.

The function of the pump or motor 10 is thus that, as illustrated inFIGURE 6, if the device is used as a pump and the gears 13 and 14 arerotated from power source, and be it assumed that they are rotated in adirection such that recess 36 would be the high pressure recess andrecess 37 would be the low pressure or inlet recess of the pump, highpressure acting on the outer peripheral surface 40 of the wear plate 30will urge the wear plate 30 to the right as viewed in FIGURE 6 to engagearcuate sealing surfaces 60 and 61 of the outer periphery of the wearplate with the inner peripheral surface 25 of the pump cavity 24 andprovide thereby a sealing engagement between surfaces 60, 6'1 andsurface 25. When this sealing engagement takes place, fluid pressure canthen flow from the high pressure recess 36 between the sealing surfaces59, 5'8 and inner peripheral surface 25 of the pump cavity relievedareas 53 and 54 on the wear plate since a fluid passage as indicated at94 is defined by the displacement of the surfaces 59 and 58 from thesurface 25. High fluid pressure in the relieved areas 54, 53 will thusbe conducted by means of the access recesses 75, 76, 77 and 78 under theseal 80 to move the seal into engagement with the face 26 to define highand low pressure zones in the face 47 of the wear plate. Thus at thistime, looking at FIG- URE 7, the high pressure zone will extend betweenthe groove 66 and the outer peripheral surface 40 of the wear plate 30on the face 47 from the radial groove section 72 counter-clockwisearound the periphery of the wear plate 30 to the radial groove 73, thusdefining a pressure loading high pressure area on the face of the wearplate which is offset with respect to the center of the gears 13 and 14to compensate for the high pressure on the opposite side of the wearplate or on face 45 engaging the gears 13 and 14. The low pressure zoneat this time is defined as the area between the groove 66 and the outerperipheral surface 40 of the wear plate 30 extending between groove 72and clockwise along the outer peripheral surface to the groove 72 andgenerally in the area of recess 55 provided in the wear plate. 5

Referring again to FIGURE 6, if the direction of the gears would bereversed and recess 37 then being the high pressure recess and recess 36the low pressure recess, the wear plate 30 would be moved to the left asviewed in FIGURE 6 and arcuate sealing surfaces 59 and 58 would thus beengaged with the peripheral surface 25 ofthe cavity 24 and a fluidpassage would then be defined between sealing surfaces 60 and'61 and theperipheral sur-' face 25 to the relieved areas 54 and 53 on the wearplate. Thus it will be seen that in either direction of rotation of thegears of the pumpor the gears of the motor, the Wear plate will shiftradially within the pump cavity 24 to engage a pair of arcuate sealingsurfaces as, for example 58 and 59 with the inner peripheral surfaces ofpump cavity to therefore provide an essential seal to seal off the highand low pressure zones of pressure loading on the face of the wear plate30. This radial movement is allowed because the clearance 43 betweenbores 41 and'42 and gear journals 16 and 16a, as shown in FIGURES 2 and9, per

mits the wear plate 30 to shift'radially to one side or the other of avertical center line 43a, FIGURE 9, depending upon the direction ofrotation of the gears.

The wear plate further moves in a transverse direction against the gearside faces 32 to provide the pressure loading function essential toeflicient pump operation by providing a seal of the side faces 32 of thegears against the face 47 on the Wear plate. The transverse movement ofthe wear plateinto engagement with'the gears is fur ther aided by thefluid pressure which is conducted'by the access recesses under the seal80. In other words, a component of force is added to move the platetransversely due toengagement of seal 80 with face 26.

As previously pointed out, the groove 66 has a generally symmetricalshape with respect to axis 65 to make the reversible operation possible.The access recesses 75, 76, 77 and 78 are located between the pairs ofarcuatesealing surfaces 58, 60, 59, 61 so that admission of high fluidpressure under seal 80 will take place regardless of the direction ofrotation and regardless of which of the pairs of arcuate sealingsurfaces is engaged with the inner peripheral surface 25 of the cavity24.

The compound movement of the wear plate 30 in both a radial and atransverse direction is'utilized in a novel manner to supply high fluidpressure to the access recesses 75, 76, 77 and 78 through the clearanceprovided between the pair of sealing surfaces which are not engaged withthe inner peripheral surface of the pump cavity at a particular time.Thus the radial movement of the wear plate 30 has a dual purpose in thatit provides for engagement between the peripheral sealing surfacesandthe inner peripheral surface 25 of cavity 24 to provide an essentialfluid seal and likewise opens fluid passages to conduct high pressurefluid to the desired locations on the wear. plate.

The arms 81, 82, 83 and 84 on the seal. 80 have an additional sealingfunction in that the end faces98which are provided thereon define acontinuation of the lip 88 which is adapted to engage the innerperipheral surface 25 of the cavity 24 at the same time the arcuateperipheral sealing surface for the particular armis engaging theperipheral surface 25 and thereby to aid in the sealing function of thearcuate sealing surfaces and ensure a good fluid seal.

It will be apparent that when the device 10 is utilized as a fluid motorthe same action of the wear plate 30 takes place, the recesses 36 and 37being interchangeably high and low pressure recesses depending upon thedirection of rotation of the motor desired and therefore which of therecesses will be supplied with high fluid pressure.

It will thus be apparent that the present invention provides a novel andimproved type of wear plate pressure loaded fluid pump or motor wherein,due ot the symmetrical design of the wear plate and its particularstructural differences over those known in the prior art, the pump ormotor is reversible while at the same time maintaining eflicientoperation due to pressure loading zones on the wear plate effectivelyproviding a seal between the side faces of the gears and the wear plate.Due to the fact that the wear plate may be made by casting methods,powdered metallurgy, or a stamping type of operation the reversibleoperation with pressure loading is provided at a very reasonable cost ascompared to structures known in the prior art.

The seal member has been conveniently designed as a one-piece fluidseal. Due to the shape of seal member 80 including lips 87 and 88, theseal.member may be made of a semi-resilient material which may be ofvarious combinations of rubber and synthetic materials having goodsealing characteristics so that the sealing face 87 will provide aneffective seal. Thus with the one-piece seal 80 the present inventionhas incorporated both the sealing function and the preloading functionnecessary with a wear plate type of pump eliminating the necessity ofadding aseparate preloading spring. As before stated, the seal member 89may be made out of any known rubber or synthetic material to provide theinherent properties necessary for both the preloading function and thesea-ling function. However, the shape of the seal 80 in cross section isso designed that it may be of uniform material composition'throughout,thereby eliminating the necessity for an expensive type of seal to beutilized in the wear plate type pump.

Illustrated in FIGURE 16 is an optional type of onepiece seal to beutilized in groove 66 comprising a generally rectangular cross sectionseal 80A having a scaling face 86A thereon adapted toengage face 26 ofbody 11. The seal 80A has'side faces 87A and 88A adapted to engage theside walls 91 and 92 respectively of groove 66. Thus in assembly, due tothe resilient nature of the seal 88, the sides 87A and 88A will bedeflected toward the center of seal 80A as illustrated in FIGURE 16 andthus provide an axial force inherent-in seal 80A tending to move seal80A out of groove 66 and into engagement With face 26. Thus a seal 80Aof simple shape is provided which :can perform both the preloadingfunction and the fluid pressure activated function-in a similar mannerto the seal described in FIGURES 14 and 15.

In FIGURES 17, 18, 19, 20, 21, 22, 23, and 24a two piece type of sealconstruction is illustrated somewhat similar to that utilized in theabove mentioned copending application of common assignee. In the twopiece seal modification a sealing member is utilized which is ofcomplementary shape to the shape of the groove 66 in the wear plate.This member 110 wouldbe constructed of a material having goodanti-extrusion characteristics and assembled in the groove 66 above aresilient member -111. Resilient member 111 is also of complementaryshape to the groove 66 provided in the wear plate 30. Resilient member111 has an upper face 115 and a lower face 116. Provided on the lowerface 116 is a series of projections 117. The projections 117 areprovided equally spaced over the entire continuous extent of theresilient member 111. The face 115 is adapted to be engaged by thesealing member 110 when the sealing member 110 and resilient member 111are assembled in groove 66 as viewed in FIGURE 23. The resilient memher111 further includes a pair of lips 120 and 121 which are adapted toengage the sides 91 and 92 of the groove to provide a fluid seal. Asviewed in FIGURE 23 the ends of the arms on the resilient member 111 areclosed to form a sunface 130 and to close the fluid chamber defined bygroove 66 and the resilient member 111. Surfaces 130 are adapted toengage inner peripheral surface 25 in a like manner as surfaces 98 onseal 80.

Referring to FIGURE 22 resilient member 111 and seal 110 are shown inassembly in groove 66. Lips 120 and 121 on resilient member 111 engagethe side walls 91 and 92 of groove 66 and together with the bottom 93 ofthe groove define the fluid channel underneath the resilient member 111so that when fluid is conducted through the channel the resilient member111 will be moved outwardly of groove 66 to move seal 110 intoengagement with the face 26 on body 11. In assembly of the resilientmember and the seal into the groove 66, the projections 117 engage thebottom 93 of groove 66 and are deformed in assembly so that thepreloading function will be provide-d by an inherent axial force inmember 111 tending to move resilient member 11 out of groove 66. Thetwo-piece seal comprising the resilient member 111 and seal 119 works ina similar manner as the one-piece seal 80 to define pressure loadingzones on the face of wear plate 30.

It will be apparent to those of ordinary skill in the art that the pumpor motor may be supplied with a second wear plate identical to wearplate 30 to be assembled between cover 12 and gears 13 and 14 whichwould function in a like manner to wear plate 30 and provide pressureloading of the gears on each side face thereof.

Various of the features of the invention have been particularly shownand described; however, it should be obvious to one skilled in the artthat various modifications may be made therein without departing fromthe scope of the invention. 7

We claim:

1. A reversible fluid pump or motor device having a cavity therein beingdefined by an inner peripheral surface, rotatable means in said cavity,an end wall enclosing said cavity, a seal plate disposed between saidrotatable means and said end wall, said plate having opposed faces, oneof said faces of said plate having seal means therein engageable withsaid end wall to define high and low pressure zones on said plate toprovide pressure loading of said rotatable means, means forcommunicating high pressure fluid to said high pressure zone, said platebeing adapted to move radially in said cavity, said plate having aportion of the periphery thereof recessed to define the limits of aplurality of arcuate sealing surfaces on opposite sides of the peripheryof said plate, said plate further being adapted for axial movementtoward said rotatable means to provide a wear sealing engagement of theother face with said rotatable means whereby in one direction ofrotation of said rotatable means the high pressure fluid will move saidplate radially to engage said sealing surfaces along one side of theperiphery thereof with said inner peripheral surface to provide a sealbetween the low and high pressure zones of said plate and when saidrotatable means is rotated in the other direction the high pressure willmove the plate radially to engage the sealing surfaces on the oppositesides of said plate with said inner peripheral surface to provide afluid seal therebetween whereby pressure loading of said rotatable meansis provided in either direction of rotation of said rotatable means.

2. A device as claimed in claim 1 wherein said means defining pressurezones on said plate comprises a groove, a sealing means in said grooveand means to communicate fluid pressure to said groove to move saidsealing means outwardly with respect to said wear plate to engage saidend wall and provide a fluid sealing between high and low pressure zoneson said plate.

3. A device as claimed in claim 1 wherein when said plate has been movedradially to engage said inner peripheral surface, a fluid communicatingchannel is defined by the clearance between the arcuate sealing surfaceson the wear plate and the inner peripheral surface on the opposite sideof said plate with respect to those arcuate sealing surfaces engagingsaid inner peripheral surface whereby high pressure communication to thesealing means is enhanced.

4. A device as claimed in claim 2 wherein a pair of arcuate sealingsurfaces are provided on opposite sides of said plate, said means tocommunicate fluid pressure to said groove being located between thepairs of sealing surfaces on the opposite sides of the periphery of saidplate whereby high pressure fluid will be conducted to saidcommunicating means in either direction of rotation of said rotatablemeans.

5. A device as claimed in claim 2 wherein the groove on the face of saidplate is symmetrical.

6. A device as claimed in claim 1 in which said plate has means definingbores therein, said rotatable means having journals, said journalsextending through the bores in said plate, the bores in said plate beingof larger diameter than said journals so as to provide for radialmovement of said plate with respect to said rotatable means.

7. In a fluid pressure energy translating device including a pair ofrotatable means and an end wall, a plate in said device between said endwall and said rotatable means, said plate being provided with meansdefining a pressure zone thereon by engagement of said means with saidend wall, said means comprising a groove in the face of said plateadjacent said end Wall, said groove having side walls, a one-piece sealin said groove adapted to engage said end wall, said seal defining achannel in said groove for communication of fluid pressure, said sealhaving a face adapted to engage said end wall and means adapted toengage the side walls of said groove whereby when said seal is assembledin said groove said means engaging the sides of said groove is deflectedtoward the center of said groove to provide an axial force urging saidseal in said groove outwardly thereof toward said end wall whereby whensaid device is assembled said sealing means will provide a preload byurging said plate into engagement with said rotatable means prior to anyfluid pressure being developed within said device.

8. A device as claimed in claim 7 wherein said seal has a generallyU-shaped cross-section, the sides of said U being engageable with theside walls of said groove.

9. A device as claimed in claim 7 wherein said seal has a generallyrectangular cross section.

10. In a fluid pressure device an assembly including a fixed surface anda member adjacent said fixed surface, said member being adapted to movetoward and away from said fixed surface, a seal surface on said membergenerally parallel to and adjacent said fixed surface, a source of fluidpressure, means defining a groove in said seal surface, said groovehaving side walls, a one-piece seal in said groove, means connectingsaid groove to the source of fluid pressure whereby fluid pressure insaid groove will move said seal outward of said groove to engage saidfixed surface and thereby define zones of differing pressures on saidseal surface, said one-piece seal having means t-hereon engaging saidside walls, whereby when said device is assembled said means on saidseal will be deflected toward the center of said groove by said sidewalls to provide an inherent axial force in said seal attempting to movesaid seal out of said groove to thereby provide a preloaded engagementof said seal with said fixed surface prior to operation of said device.

11. A fluid pressure device as claimed in claim 10 wherein said seal hasa general U-shaped cross-section and said means on said seal comprisinglips engageable with said side walls.

12. A fluid pressure device as claimed in claim 10 wherein said seal hasa generally rectangular cross section.

References Cited UNITED STATES PATENTS Kane 103126 Miller et a1. 103126Murray 103126 Aspelin 103126 Nagely 103126 Gordon 103126 Miller 103126Lauck 103126 Trick 103126 Paschke 123-8 Kaechele 103126 Clark et a1.103126 DONLEY I. STOCKING, Primary Examiner.

10 W. I. GOODLIN, Examiner.

1. A REVERSIBLE FLUID PUMP OR MOTOR DEVICE HAVING A CAVITY THEREIN BEINGDEFINED BY AN INNER PERIPHERAL SURFACE, ROTATABLE MEANS IN SAID CAVITY,AN END WALL ENCLOSING SAID CAVITY, A SEAL PLATE DISPOSED BETWEEN SAIDROTATABLE MEANS AND SAID END WALL, SAID PLATE HAVING OPPOSED FACES, ONEOF SAID FACES OF SAID PLATE HAVING SEAL MEANS THEREIN ENGAGEABLE WITHSAID END WALL TO DEFINE HIGH AND LOW PRESSURE ZONES ON SAID PLATE TOPROVIDE PRESSURE LOADING OF SAID ROTATABLE MEANS, MEANS FORCOMMUNICATING HIGH PRESSURE FLUID TO SAID HIGH PRESSURE ZONE, SAID PLATEBEING ADAPTED TO MOVE RADIALLY IN SAID CAVITY, SAID PLATE HAVING APORTION OF THE PERIPHERY THEREOF RECESSED TO DEFINE THE LIMITS OF APLURALITY OF ARCUATE SEALING SURFACES ON OPPOSITE SIDES OF THE PERIPHERYOF SAID PLATE, SAID PLATE FURTHER BEING ADAPTED FOR AXIAL MOVEMENTTOWARD SAID ROTATABLE MEANS TO PROVIDE A WEAR SEALING ENGAGEMENT OF THEOTHER FACE WITH SAID ROTATABLE MEANS WHEREBY IN ONE DIRECTION OFROTATION OF SAID ROTATABLE MEANS THE HIGH PRESSURE FLUID WILL MOVE SAIDPLATE RADIALLY TO ENGAGE SAID SEALING SURFACES ALONG ONE SIDE OF THEPERIPHERY THEREOF WITH SAID INNER PERIPHERAL SURFACE TO PROVIDE A SEALBETWEEN THE LOW AND HIGH PRESSURE ZONES OF SAID PLATE AND WHEN SAIDROTATABLE MEANS IN ROTATED IN THE OTHER DIRECTION THE HIGH PRESSURE WILLMOVE THE PLATE RADIALLY TO ENGAGE THE SEALING SURFACES ON THE OPPOSITESIDES OF SAID PLATE WITH SAID INNER PERIPHERAL SURFACE TO PROVIDE AFLUID SEAL THEREBETWEEN WHEREBY PRESSURE LOADING OF SAID ROTATABLE MEANSIS PROVIDED IN EITHER DIRECTION OF ROTATION OF SAID ROTATABLE MEANS.